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Date:      Tue, 25 Nov 1997 20:01:42 -0600
From:      David Kelly <dkelly@hiwaay.net>
To:        "keith Spencer" <bsd@smmcroute.smmc.qld.edu.au>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: adding serial ports..tricky? 
Message-ID:  <199711260201.UAA11940@nospam.hiwaay.net>
In-Reply-To: Message from "keith Spencer" <bsd@smmcroute.smmc.qld.edu.au>  of "Tue, 25 Nov 1997 13:04:05 GMT." <199711250135.LAA08108@smmcroute.smmc.qld.edu.au> 

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keith Spencer writes:
> Hi folks,
> I have a 486 SX 33 with 2 serial ports an LPT1 8 Mb RAM
> 500Mb IDE drive Floppy VGA card a modem configured etc.
> 
> I wish to add a couple of extra serial ports...my tech man says 
> simply put a another super I/O board in and disable the drive bits.
> But he is unsure that it is that simple in FBsd UNIX. I know I'd have

It is that simple if you have the spare I/O addresses and IRQ's. And 
that's usually the cheapest way to get 2 more ports. A friend picked up 
a $15 or $20 super I/O board with 16550's that had jumpers for the high 
IRQ's 10, 11, 12, 14, and 15. Maybe that's common now.
 
> to re-build the KERNEL but is the hardware addition simply as he 
> suggests?...any knowledge out there...Thanks

I use an STB 4-com which features a StarTech ST16C554CJ quad 16550. 
Used to be around $100 when you could find them. Either Jameco or JDR 
Microdevices offer serial boards with StarTech chips now. Have never 
tried them. Some are pictured with two StarTech chips, would expect 
those boards to require two IRQ's. Maybe not.

This is what I did to my kernel config file:

# unchanged standard sio stuff
device          sio0    at isa? port "IO_COM1" tty irq 4 vector siointr
device          sio1    at isa? port "IO_COM2" tty irq 3 vector siointr

# STB 4-com
options         COM_MULTIPORT      #code for some cards with shared IRQs
device  sio2    at isa? port 0x1a8 tty flags 0x205 irq 10 vector siointr
device  sio3    at isa? port 0x1e8 tty flags 0x205
device  sio4    at isa? port 0x2a8 tty flags 0x205
device  sio5    at isa? port 0x3e8 tty flags 0x205



--
David Kelly N4HHE, dkelly@hiwaay.net
=====================================================================
The human mind ordinarily operates at only ten percent of its
capacity -- the rest is overhead for the operating system.





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